Rectifier



H. P. DONLE.

RECTIFIER4 APPLICATION man MAY3|,1921.

Patented June 27, 1922.

UNITED sTATEsg-PATENT OFFICE.'

mmm 1. DoNLE, or uranium, oNNnc'rrcUT. y

BECTIFIEB'.

To all who/mit may concern.'

Be it known that I, HAROLD P. DONLE, a

citizen of the United States of America, re-y siding at Meriden, Connecticut, have invented a new and useful Rectifier, of which the.

. lizes two cold electrodes within a vacuum tube. I make use of the fact that negative j particles tending to leave an electrode or move away from itsvicinity will move in lines substantially at right angles to the electrode surface. By suitably forming and locating the electrodes I have found that I can secure predominatingone-way transmissionand consequently rectification.

I have been able to obtain rectification in this way with several different constructions. v Figure 1 illustrates one form of apparatus involving my invention for half-wave rec tificatiomthe tube being shown in longitudinal section and the circuit being vshown diagrammatically Figs. 2 and3 are longitudinal sectional views of tubes with other forms of electrodes; and

Fig. 4 is a view similar toFig. 1 but showing a tube and circuit for full-wave rectification.

'The tube 6 may be of the ordinary type of glass tube exhausted or evacuated to a suitable degree. I have found a pressure of approximately one millimeter of mercury to be satisfactory. An inert gas may be present at a corresponding pressure.

The electrodes 7 and 8 are of suitable metal, such as molybdenum, tungsten or other durable metal. I provide the electrodey 8 with a flange 9, so that it is in the form of a cup, which has a hole 10 in the center of its active surface. The other electrode may have a flange 11. These cups are placed with their faces so close together as to prevent or minimize ionization between the adjacent surfaces.

Fig. 1 shows a circuit with an'A. C. generator -12 and a transformer 13. .When the tube is connected as shown in this figure, a pulsating direct current flows in the work circuit. When this type of tube is in opera- Specicat'ion of Letters Patent. Patented June 27', 1922. Application led Hay 31, 1921. Serial No. 474,068. Y l

tion the ionization glow very nearly fills the cathode cup 8. .This low is separatedv from the walls ofthe cat ode bya dark space. Projectin from the anode through the hole 10 a smal conical column of veryintense light will be seen, and it is impossible, while Watching the opera-tion, to distinguish' the exact junction between the general glow throughout the interior of the cathode and this brilliant column emanating from the anode. l

My theory of operation is that when the pierced electrode 8 is subjected to the negative potential of the A. C. wave to be recti. fied, vthus making the solide'lectrode 7 the anode, all negative particles within the cathode 8 will be repelled from itto the center and literally forced through the hole to the anode 7. The particles moving from ythe cathode to the anode under normal conditions in a tube lof approximately 1i inches internal diameter will collide with ga's'molecules after they have reached a 'distance of about gths of an'inch from the inside wall of the cup 8. The electrons resulting from this collision will pass axially of the tube and through the hole 10 to the anode 7 The small bright cone-shaped discharge marks the -position of-very violent collisions, as thef particles are mov1ng through a comparatively restricted zone and all collisions therein take place with great violence.

When the potential of the current'to be rectified reverses and the electrode 8 becomes positive the few electrons which come through the-hole 1() find a weak field tending to draw them in all directions distributed over a large curved area, and they do not get up sutlicient velocity for ionization.

Other electrons pass directly to the electrode 8, which is now positive, without causing ionization. Consequently, no current or only small current passes through the tube in this inverse direction;

For high voltages the electrodes should be as close together as possible, to eliminate av two-way discharge between the faces. The electrodes may be initially placed or adjusted farther apart for'lower voltages where the electrons will necessarily be required to traverse a longer distance in order to absorb sufficient energy to ionize the gaseous atoms. With higher potentials the electrons start out at high velocities and acquire sufflcient energy a very short distance from their starting points. In such cases the electrodes must be very close together.

In the construction of Fig. 2 the electrode 7 is-shown solid, and electrode 8 is shown with a recess 10. In this case the space between the adjacent faces of the electrodes sless than thefree mean ionization.

In the formshown in Fig. 3 the negative electrode 7 is in the form of a cylinder or tube with one end sufficiently close to the anode to bring itwithin the dark space. The field 'from the anode extends axially of the cathode in the recessed chamber 10".

The tube andcircuit of Fig. 4 is for complete or full wave rectification. The central tubular electrode 8a constitutes the cathode, and the discs 7a the anodes at opposite ends, so as to use both sides of the A. C. wave.

In any case the electrodes should be of sufficient area to-avoid overheatin under the conditions for which the tube is esigned.

I have found that the tube of Fig. 4 may also be used for doubling the frequency of the impressed A. C. by providing a transformer in the work clrcuit.

The theor` of operation which I have set forth'as to ig. 1 also applies to the other forms shown. For instance, when the electrode 8' of Fig. 2 becomes negative, electrons are vigorously repelled from the metal to the center of the orifice 10, and thence axially toward the anode 7. In this movement they set up extensive ionization and consequently the device becomes a good conductor for the half-wave applying negative potential to the electrode. 8. On the other hand, when 7 is negatively charged, electrons repelled from 7 to the adjacent face of 8 travel so short a distance that ionization is negligible or absent; such of them as are propelled into the orifice 10 are not strongly attracted by 8 in any given direction and cause little, if any, ionization. Consequently, for the half-wave which makes 7 (instantaneously) a cathode, the conductivity of the tube is negligible.

In the same way the action of Fig. 3 may be understood. The chamber 10 is the active locus of ionization when the electrode 8 is charged negatively, but little or no ionization is produced when electrode 7 is negative. The cylinder 8" may be placed close to or in contact with the glass wall of the tube 6, since the inside of the cathode 8 is most highly active in producing the effects of rectification which I have discovered. When it is supported freely in the' interior of the tube, the few electrons which may be outside the tubular electrode seem to play no substantial part in the operation of the device. v

In Fig. 4 the two anodes 7a nately, the electrons from or path required for operate altern ear the cathode 83 being" driven 4continually toward the center of the tube and alternately along the axis to whichever of the anodes isthe more strongly charged positively. I have found this form of-tube to be somewhat more efficient than two single-anode tubes connected in a similar divided-transformer circuit, perhaps because some ionization is residual and carries over from one alternation to the next, and because each anode as it becomes negatively charged aids in repellin the electrons toward the other.

n order to determine whether or not the electrodes in any particular device are properly located i. e. so closely spaced as to minimizenionization in the inverse current fiow direction, one may apply across the terminals of the device under test a direct current potential of the order of the alternating current potential to be rectified. When the electrode 7 is made positive the tube will ionize as above described and considerable current will fiow. However, when electrode 7 is made negative there will be substantially no ionization and negligible or no current will flow, if the spacing between the electrodes is sufficiently small for.

proper operation of my rectifier.

I claim: f

1. In a rectifier, a vacuum tube, two electrodes within said tube and having their adjacent faces arranged so close together as to minimize ionization between them under one direction of applied potential, one of said electrodes having an orifice providing an ionizing path along its axis.

2. In a rectifier, a vacuum tube, two electrodes within said tube and having their adjacent faces of unequal area and arranged so close together as to minimize ionization between them under one direction of applied potential, one of said electrodes having a passage to provide an ionizing path along its axis.

3. In a rectifier, a vacuum tube, a hollow cathode and an anode arranged opposite thereto at a distance less than the mean free path required for ionization under electromotive forces impressed in one direction 4. In a rectifier a tube, two electrodes within said tube with their adjacentv faces apart a distance less than the mean free path required for ionization in one direction, the cathode having an ionizing passage.

5. In a rectier, a tube, two electrodes within said tube with their adjacent faces spaced apart a distance small enough to minimize ionization under electromotive forces impressed in one direction, the cathode having a passage through the face adjacent said anode, and the anode having a plane face.

6. In a rectifier, a plane faced electrode, a cylindrical electrode arranged with one end adjacent the other electrode central ionizin space.

7. In a rectier, tWo plane electrodes and a tube electrode between them having an ionizing passage. v

8. In a rectifier7 a tube having a transversel disposed anode and a longitudinally exten ing cathode with an unobstructed central zone of ionization.

9. In a rectifier, a tube, a cylindrical and having a cathode mounted therein and having an axial ionizing space2 and an anode extending substantially at rlght angles to the axis of said cathode.

l0. In. a rectifier, a tube', a tubular cathode mounted therein having a longitudinally extending ionizing space, and anodes extending transversely of said tube at opposite ends of said cathode.

HAROLD P. DON LE. 

